1. Field of the Invention
The present invention relates to a compressor and refrigeration cycle device having the same, and, more particularly, to an oil recollecting apparatus of a compressor capable of separating and recollecting oil from a refrigerant discharged from a compressing unit of the compressor.
2. Description of Related Art
A compressor is a device for converting kinetic energy into compression energy of a compressive fluid. A hermetic compressor is configured such that a motor for generating a driving force and a compression unit for compressing fluid by the driving force received from the motor are all installed in an inner space of a hermetically sealed container.
When the hermetic compressor is provided as a component in a refrigerant compression refrigeration cycle device, a certain amount of oil is stored in the hermetic compressor in order to cool the motor of the compressor or smooth and seal the compression unit. However, when die compressor is driven, the refrigerant discharged from the compressor into the refrigeration cycle device includes oil mixed in with the refrigerant. Part of the oil discharged into the refrigeration cycle device is not recollected to the compressor but remains in the refrigeration cycle device, thereby causing a decrease in the amount of oil in the compressor. This may result in decrease in compressor reliability and also degradation of heat-exchange capability of the refrigeration cycle device due to the oil remaining in the refrigeration cycle device.
Accordingly, in the related art, an oil separator is disposed at a discharge side of the compressor to separate oil from the discharged refrigerant, and such separated oil is recollected to a suction side of the compressor, thereby avoiding the lack of oil in the compressor and also maintaining the heat-exchange capability of the refrigeration cycle device.
However, when recollecting oil separated by the oil separator into the suction side of the compressor, the high pressure refrigerator is also recollected together with the oil, which results in decreasing the amount of refrigerant circulating in the refrigeration cycle device, thereby lowering a cooling capability of the compressor. In addition, temperature of suction gas in the compressor is increased to thereby raise temperature of discharge gas. Accordingly, the reliability of the compressor is degraded. Also, as the temperature increases, a specific volume of the sucked refrigerant is increased, so as to decrease the actual amount of the sucked refrigerant, thereby degrading the cooling capability of the compressor.
In an attempt to decrease pressure and temperature of oil recollected from the oil separator into the compressor, to decrease pressure and temperature of oil removed from the refrigerant, and to prevent the backflow of the refrigerant into the compressor, a decompressing device, such as a capillary tube, the related art may include a decompressing device, such as a capillary tube, is provided between the oil separator and the suction side of the compressor. However, even if the decompressing device is so located, the pressure of the oil separator is higher than the pressure of the suction side of the compressor, which causes an increase in suction temperature and suction pressure of the compressor. In particular, when driving the compressor at low speed, the amount of oil pumped is decreased in the compressor. As a result, more refrigerant is recollected than oil, thereby further degrading the cooling capabilities of the compressor and the refrigeration cycle device.
Furthermore, as the oil, which has been separated by the oil separator and then recollected, is mixed with the sucked refrigerant, it is discharged with the refrigerant via the compressing unit, thereby leaving insufficient oil in the inner space of the casing causing the reliability of the compressor to deteriorate further.